Graphs of Input Data - Box-Whisker

The box plots resulting when you select Box-Whisker from the Graphs - Graphs of Input Data submenu represent the central tendency and variability of the currently highlighted variable. As measures of central tendency, you can choose between plotting the means and medians and their respective measures of variability; standard deviations or standard errors (associated with the means), and ranges (associated with the medians). Choose one of four types of box plots to represent the distribution of the values of the currently highlighted variable.

 Median/Quart./Range. This box plot describes the central tendency of the variable in terms of the median of the values (represented by the smallest box in the plot). The spread (variability) in the variable values are represented in this plot by the quartiles (the 25th and 75th percentiles, larger box in the plot) and the minimum and maximum values of the variable (the "whiskers" in the plot).

 Mean/SE/SD. Here, the smallest box in the plot represents the mean (central tendency) of the variable, while the dispersion (variability) is represented by ± 1 times the standard error (large box) and ± 1 times the standard deviation about the mean ("whiskers").

 Mean/SD/1.96*SD. This plot will show the mean (small box in the plot) of the variable surrounded by a larger box (± 1 times the standard deviation). If the distribution is normal, then the "whiskers" in this plot represent a "95% confidence interval" defined as the variable mean ± 1.96 times the variable standard deviation.

Mean/SE/1.96*SE. Once again, this plot will show the mean (small box in the plot) of the variable surrounded by a larger box. However, in this plot, the larger box represents ± 1 times the standard error. If the distribution is normal, then the "whiskers" in this plot represent a "95% confidence interval" defined as the variable mean ± 1.96 times the variable standard error.

Many other types of box and whisker graphs are available via STATISTICA's Graphs menu graphs. For a general overview of the graphics facilities in STATISTICA, see Graphs in STATISTICA. In order to produce box plots representing the distribution of the values in cases (and not variables), use either the Graphs of Block Data - Custom Graph for Entire Row or Graphs of Block Data - Custom Graph from Block by Row option from the spreadsheet shortcut menu (instead of transposing your data file).